Classroom Questions

Questions for ‘Freshwater fish are in trouble: Here’s how we can help them’ 

an underwater photo of a river, showing salmon swirling around each other, rocks, and a sunlight-dappled surface

Salmon, lake trout and other native freshwater fishes around the world face threats due to invasive species (like bloodsucking sea lampreys), habitat loss and dams. New research highlights the importance of ongoing work to protect native fish.

Paul Souders/Stone/Getty Images Plus

By Science News Explores

To accompany ‘Freshwater fish are in trouble: Here’s how we can help them’

SCIENCE

Before Reading:

  1. Describe one specific way people might accidentally affect what chemicals show up in river water. Also describe one specific way human activities might alter how much water flows down a river.
  2. Pick one of the human impacts you described above and list two organisms that might be negatively affected by such a change. Speculate on how the altered river conditions might cause problems for one of these organisms.

During Reading:

  1. Which month marks the start of the wet season around Cambodia’s Tonle Sap Lake?
  2. Summarize how Tonle Sap Lake changes between its dry and its wet seasons.
  3. Why are these lake changes so crucial to the people living on or near Tonle Sap Lake?
  4. List two reasons that people build dams.
  5. In 2024, engineers took down several dams in the lower Klamath River. They hoped this move would open up new river habitats for fish and other wildlife. Describe an early indication that the dam removals were showing signs of achieving their environmental goal.
  6. What are riffles?
  7. What does it mean for a species to be invasive?
  8. Give one example of an invasive fish species in the United States. Then, describe one survival advantage this species has had over native fish species.
  9. How did humans help increase the population of lake trout in Lake Superior?
  10. According to David Strayer, how can kids and teens get involved in protecting freshwater fish? Give one example of an action that kids and teens can take.

After Reading:

  1. Describe how some human activity has altered the natural habitat of the Nooksack dace. What promising findings did John Gray discover while studying this minnow’s habitat? Develop a strategy based on these findings to address this minnow’s habitat loss. What materials and tools would you need to carry out this plan over a large area? Imagine you succeed and populations of Nooksack dace increase. Give an example of how this kind of positive change might trickle out and improve some other aspect of the environment.
  2. This story says there’s no one-size-fits-all approach to dealing with the described problems. With that in mind, review the strategy used to increase lake trout in Lake Superior. Then, search this story for an example of scientists trying a similar approach elsewhere, but encountering different results. Compare these results to the Lake Superior success story. Identify a factor that may have contributed to the differences in results. Then, develop an alternative strategy, or an adapted version of the same plan, that might work better in that region. Explain your reasoning for the new action plan and why you think it might work.